DESCRIPTION (Applicant's Description): This program is designed to train radiation biologists with reference to the molecular, cellular, tissue, mutagenic and carcinogenic effects of radiation. Both predoctoral and postdoctoral training will be offered. The program will be interdepartmental incorporating radiobiologic research resources in several laboratories at the Harvard School of Public Health and Harvard Medical School. Research training will be accomplished by didactic and practical courses, by special lectures and lecture series, by research seminars, by research conferences, by journal clubs and by laboratory research experience supervised by senior investiga-tors. Laboratory research will generally focus on an aspect of ongoing, funded research but provision will be made for exceptional students to follow avenues of their own innovation. The strength of the program resides in the broad experience and diversity of research pursued by a critical mass of training directors and supervisors who among them are pursing research programs in the fields of radiation chemistry and biochemistry, cellular and molecular radiation biology, mutagenesis, carcinogenesis, cytogenetics and radiation oncology. Predoctoral trainees will have a science background in physics, chemistry and/or biology. They must be acceptable to the Program Director and must meet the admissions requirements of Harvard University. Postdoctoral trainees will be admitted by application to one of the training preceptors and with the approval of the research training committee consisting of the Program Directors and Associate Directors. It is expected that admission will be competitive. Six predoctoral and 6 postdoctoral positions will be available. Trainees will be expected to pursue research and academic careers in the fields of radiation biology and radiological science including radiation oncology, nuclear medicine and medical radiation physics. Primary research facilities will include: the Laboratory of Radiobiology, Department of Cancer Biology, Harvard School of Public Health; the Laboratory of Experimental Radiation Therapy, Department of Radiation Oncology, Harvard Medical School; and the Laboratory for Experimental Nuclear Medicine, Department of Radiology, Harvard Medical School. The program will be administered through the Harvard School of Public Health. In addition to classrooms, seminars rooms, departmental and university libraries, students will have access to specialized radiation sources and a large number of fully equipped laboratories including cell and tissue culture facilities and small and large animal vivaria.